The preparation and photocatalytic performance of the Fe 2 O 3 /g-C 3 N 4 nanocomposites with different weight percentage of iron was investigated in this study. Samples were successfully synthesized using melamine and ferric nitrate as the precursors via the green and facile microwave-assisted method. The physicochemical and structural properties of the Fe 2 O 3-doped g-C 3 N 4 were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), the Brunauer-Emmett-Teller (BET) method, transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and ultraviolet-visible spectroscopy (UV-Vis). The photocatalytic activity of the Fe 2 O 3 /g-C 3 N 4 catalysts was evaluated by the degradation of methylene blue (MB) at room temperature under visible light irradiation. As expected, the assynthesized samples exhibited considerable improvement in the photodegradation of MB. The Fe 2 O 3 /g-C 3 N 4 (1.0 wt%) nanocomposite had superior photocatalytic activity, with almost 70% degradation efficiency within 90 min of irradiation. The enhanced performance was ascribed to the separation and migration of the photoinduced electron-hole pairs and taking part of the charge carriers in the chemical redox reactions at the surface of the photocatalyst. In this work, the effect of Fe weight percentage on the degradation potential was also studied, and the photocatalytic mechanism was proposed with the main reactive species •OH.